Thesium costatum A.W.Hill

Root stock slender, erect; stems few and fairly numerous, branched in the upper part, ribbed or angular, glabrous; leaves laxly arranged, linear, acutely acuminate, 3-6 lin. long, flat, glabrous, midrib prominent on both surfaces; cymules 1-3-flowered; bracts shortly adnate to the peduncle, 3-5 lin. long, otherwise similar to the leaves; peduncle shorter or a little longer than the bract, compressed, rather slender; bracteoles shorter or longer than the flowers, linear, acute, glabrous; perianth 1 1/4-1 1/2 lin. long; segments triangular-lanceolate, 3/4 lin. long, hooded, the margins with a broad flap-like fringe near the base, the hood beaked and slightly papillose; anthers 1/3 lin. long; style 3/4 lin. long, overtopping the anthers; fruits campanulate-globose, about 3 lin. long including the persistent perianth, prominently 10-ribbed, coarsely reticulate between the ribs.